Core orientation determination

ABSTRACT

A core orientator, comprising a body ( 11 ) configured to be receivable in a bore hole and to be lowered into the bore hole, the body defining a space ( 17 ) which in use is intended to receive a liquid, the space supporting a reference member ( 23 ) which is at least substantially supported by the liquid, the reference member having a reference face with a centre, the reference member being weighted such that when the space is at least partially filled by the liquid, the centre will be uppermost, a clamping means ( 29 ) adapted to clamp the reference member in position within the space on the lower end of the body being engaged with the bottom of the bore hole.

FIELD OF THE INVENTION

This invention relates to an orientation device for determining the orientation of the bore hole from which a core sample is extracted.

BACKGROUND ART

In the past various arrangements have been provided for providing an indication of the profile of the bottom of a bore hole prior to initiating a drilling action in order that on the core sample being extracted from the bore hole, the orientation can be directly determined from the orientation device. Some of these arrangements are described in the publication “Australian Drilling Manual”—Third Edition 1992—at pages 358 to 360 under the heading “Cutting Oriented Cores”

One form of orientation device which has been used in the past is known as the “Van Ruth Core Orientator” which is also disclosed in AU-240221. Another form is disclosed in US patent specification 4311201. In both cases the devices are intended to provide a record of the profile of the base of a bore hole prior to the drilling and extraction of a core from a borehole in order to assist in the accurate re-orientation of the extracted core relative to the previously extracted core when they are on the surface in order to assist in the analysis of the cores

Other forms of orientation devices have provided means of determining which part of the core is lowermost and examples of arrangements which providing such an indication are disclosed in AU-240221, U.S. Pat. No. 4,311,201, WO-00/75480 and WO-03/038232.

In addition, WO-03/038232 discloses a further arrangement which enables the inclination of the bore hole to be determined.

Furthermore, AU-240221 and WO-03/038232 disclose an association between an orientation device such that the orientation device can be used in association with a core drill where the orientation device initially records the characteristics of the bore hole and is connected to the drill string such that subsequently the drill can be operated to cut a drill core and the orientation device can be extracted from the bore hole with the cut core at the conclusion of the drilling

The discussion throughout this specification, of the background and prior art to the invention is intended only to facilitate an understanding of the present invention. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge in Australia and the world as at the priority date of the application.

It is an object of this invention to provide an orientation indicator which is simpler in its operation and from which it is more readily possible to determine the orientation of a bore hole.

DISCLOSURE OF THE INVENTION

Throughout the specification and claims, unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Accordingly the invention resides in a core orientator, comprising a body configured to be receivable in a bore hole and to be lowered into the bore hole, the body defining a space which in use is intended to receive a liquid, the space supporting a reference member which is at least substantially supported by the liquid, the reference member having a reference face with a centre, the reference member being weighted such that when the space is at least partially filled by the liquid, the centre will be uppermost, a clamping means adapted to clamp the reference member in position within the space on the lower end of the body being engaged with the bottom of the bore hole.

According to a preferred feature of the invention the lower end of the body supports a face orientator having a face which in use is able to be forced into contact with the bottom of the bore hole and to provide an indication of the profile of the end of the bore hole.

According to a preferred feature of the invention the reference member has a configuration of a sphere. According to a preferred feature of the invention the reference face of the reference member is provided with a set of circular graduations concentric with the centre.

According to a preferred feature of the invention the core orientator is to be used in a bore hole in which liquid is present, and the body is adapted to permit the entry of the liquid into the space on being located in the liquid within the bore hole.

According to an alternative preferred feature of the invention the space accommodates the liquid. According to a preferred feature of the invention the space is defined by a closed reservoir having a wall which is deformable on engagement with the clamping means in order to fixable engage the reference member within the space, said deformation being permanent said space containing the reference member and liquid. According to a preferred feature of the invention the reservoir has the configuration of a sphere. According to a preferred feature of the invention the reservoir is removable from the body wherein in use the position of said deformation provides an indication of the position of the reservoir relative to the body. According to a preferred feature of the invention the clamping means is associated with a deformation means which is supported in the space proximate the reservoir and which is movable into engagement with the wall on the clamping means clampingly engaging the wall to cause the deformation means to cause said deformation of the wall. According to a preferred feature of the invention the deformation means comprises a separable element which on causing said deformation may be retained by the deformation. According to a preferred feature of the invention the deformation means comprises a ball element supported in the space between the reservoir and the clamping means.

According to a preferred feature of the invention the reference member is magnetised to have a North and South Pole at opposed sides of the reference member, said reference member bearing indicial indicative of the location of the North and/or the South Pole. According to a preferred feature of the invention the Poles are substantially equidistant from the reference face.

According to a preferred feature of the invention the face orientator comprises a plurality of axial pin elements which are slidably received within the body such that a force of a predetermined magnitude is required in order to slidably move the elements within the body.

According to a preferred feature of the invention the clamping means comprises a clamping member slidably received in the body and extending between the one face and the space wherein the end of clamping member within the space is adapted to be engageable with the reference member, the upper end of the space being adapted to support the uppermost face of the reference member when engaged by the clamping member. According to a preferred feature of the invention the clamping member comprises an upper portion and a lower portion, both upper and lower portion being slidably received within the body along a common axis, a first locking means provided between the body and the one portion to retain the one portion in a position, the other portion being biased to an outermost position with respect to the face.

According to a preferred feature of the invention the other end of the body is associated with a first tube clamping means which is adapted to clampingly retain the body within the inner tube of a core drill, said first tube clamping means being dis-engagable from the inner tube on the clamping means, clamping and engaging the reference member. According to a preferred feature of the invention a second clamping means is provided between the body and the inner tube, the second clamping means is adapted to clampingly engage the body within the tube to prevent axial movement of the body from the inner tube and permit axial movement of the body into the inner tube. According to a preferred feature of the invention the body is associated with a second clamping means which is adapted to retain the body within the inner tube of a core drill to prevent outward displacement of the body with relative to the inner tube.

According to a preferred feature of the invention the density of the reference member approximates the density of the liquid.

The invention will be more fully understood in the light of the following description of several specific embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The description is made with reference to the accompanying drawings of which:

FIG. 1 is a section elevation of a core orientator according to the first embodiment with the reference member in an unclamped position;

FIG. 2 is a sectional elevation of the core orientator according to the first embodiment with the reference member in the clamped position;

FIG. 3 is a sectional elevation of the core orientator according to the first embodiment and as shown at FIG. 1 in association with an inner tube of a core drill;

FIG. 4 is a sectional elevation of a core orientator according to the second embodiment with the reference member in the unclamped position; and

FIG. 5 is a sectional elevation of the core orientator according to the second embodiment with the reference member in the clamped position;

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

The first embodiment as illustrated at FIGS. 1, 2 and 3 comprises a core orientator which can be utilised in determining the orientation and position of a core in a bore hole (including the inclination and azimuth of the portion of the bore hole from which the core is extracted) prior to extraction of the core from the bore hole in order that the position can be replicated on the surface when it becomes necessary to identify the original position of the core within the ground.

The embodiment comprises a body 11 which is intended to be lowered down a bore hole and which has a lower casing portion 13 which supports a face orientator generally corresponding to a “Van Ruth Core Orientator” and which comprises a set of elongate rods 15 which are slidably supported within the lower casing portion 13 of the body 11 such that they can be displaced axially with respect to the body. The slidable engagement of the rods 15 within the body 13 is effected with some frictional resistance in order that a predetermined magnitude of force needs to be applied in order to effect the displacement of the rods 15 within the body.

The interior of the body, inward of the lower end of the lower casing portion 13, defines a space 17 which is of generally a cylindrical configuration. The end face of the space remote from the lower casing portion 13 of the body 11 is formed of a reduced diameter portion 19 to define an annulus. The body is configured such that in use, when the core orientator is lowered into a bore hole containing a liquid, the liquid will fill the space 17. The space is associated with a tapered space 21 which is above the space 17 and open to the space 17 through the annulus. The space 17 accommodates a reference member 23 which is spherical and which has a density a little greater than the density of the liquid which is likely to be anticipated in the bore hole in order that it will be substantially supported by the liquid within the space.

The reference member 23 is weighted and is provided with a reference face having a centre which will be uppermost when the reference member is supported by the liquid. The reference face 23 is provided with a set of circular graduations (not shown) which are concentric with the centre and which represent angular displacements away from the centre when supported in the liquid and which can provide an indication of the inclination of the bore hole when observed through the annulus. In addition, the reference member 23 accommodates a magnet or alternatively is magnetised to have a North and South Pole which are located at opposed side of the reference member 23 and are spaced equidistant from centre of the reference face 23. In addition the reference face is provided with at least one marking representative of the markings of a compass. As a result when the reference face is observed though the annulus it can provide an indication of the azimuth of the bore hole.

The lower casing portion 13 of the body 11 is formed with a central bore which slidably accommodates a clamping rod 27 which is restrained frictionally at the one end by an O-ring 31 supported within the bore. The one end of the clamping rod is located adjacent the space 17 and supports a bearing member 29 which is in opposed relation to the reference member 23. The other end of the clamping rod 27 is accommodated within the bore. The bore also slidably supports an actuating rod 35 which extends beyond the lower end of the lower casing portion 13. A pair of first biasing springs 37 are provided between the clamping rod 27 and the actuating rod 35 and serve to resiliently bias the actuating rod to its outermost position with respect to the lower casing portion at which position it extends beyond the lower ends of the rods 15 of the face orientator as shown at FIG. 1.

In use the body 11 is clampingly supported in the lower end of a drill tube 50 (see FIG. 3). On the body being lowered into a bore hole it is carried with the inner tube 50 of the drill string (see FIG. 3) to the bottom of the bore hole. On the drill tube reaching the bottom of the bore hole the weight of the inner tube is borne by the body which will cause the actuating rod 35 to slide into the body until it reaches an intermediate position at which the free ends of the elongate rods 15 will engage the surface of the end face of the bore. On further movement of the actuating rod 35 into the body the array of the outer ends of the elongate rods will adopt a profile according to the profile of the end face. On the actuating rod moving to its inner most position beyond the intermediate position the compressive force applied by the first biasing springs 37 will move the clamping member 27 to cause the bearing member 29 to clamp the reference member against the annulus 19. Because of the restrictive sliding support provided to the clamping rod by the O-Rings the reference member is fixed in the clamped position and the position of the reference face relative to the annulus will be representative of the inclination and azimuth of the bore hole at that position

The other end of the lower casing portion is closed by a plug 39 which is slidably accommodated within an upper casing portion 14 of the body 11 for axial movement relative to the plug. The lower end face of the plug 39 of the plug defines the tapered space 21 above the space 17 and the plug is separable from the body 11 to provide visual access to the portion of the reference face of the reference member 23 bounded by the annulus 19. The inner end of the tapered space resiliently supports a second bearing member 40 which is movable resiliently in the axial direction in the direction of the space 17. The inner end of the second bearing member 40 will bear on the upper face of the reference member, when not clampingly engaged, to hold the reference member away from the annulus. Because of the resultant point contact between the reference member 23 and the second bearing member 40 the reference member will be able to rotate as a result of it being weighted such that the centre is maintained uppermost.

A shear pin 38 is mounted between the upper casing portion and the plug and serves to maintain the upper casing portion at its inner most position relative to the lower casing portion 13 as shown at FIG. 1. The upper end of the upper casing portion 14 is closed by an end element 16 and a second biasing spring 42 is located between the plug and the end element 16 of the body and applies a biasing force between the lower and upper casing portions which would cause them to separate axially if not for the shear pin.

The body is provided with a first tube clamping means provided at the upper end of the body 11 which is to clampingly engage with the inner bore of an inner tube 50 to retain the body in position within the inner tube. The first tube clamping means comprises a locking cap 41 which is supported from the uppermost end of an extension 44 which is fixed at its lower end to the plug 39 and is slidable over the end element 16. The locking cap 41 is formed with a downwardly extending skirt 49 which is received over the upper end of the body and the opposed faces of the skirt and the body are of a complementary tapered configuration such that on the cap moving upwardly from the body the opposed faces will separate. The skirt is formed with a set of circumferentially spaced apertures which each accommodate a locking ball 51 which is to be entrapped between the tapered face of the upper end of the body and the inner tube 50. A third biasing spring 47 is provided between the end cap 41 and the end element of the body to pre-load and retain the shear pin 38. When the locking cap 41 is held closely adjacent the upper end of the body (as shown at FIG. 1) and with the upper casing portion being retained in its engaged position with the plug 39 by the shear pin 38, the locking balls are clampingly engaged between the inner tube and the upper end of the body to hold the body in position 11 within the inner tube 50.

On the actuating rod 35 moving inwardly into the body to cause the reference member 23 to be clampingly engage with the annulus, the reference member 23 will bear on the second bearing member 40 and thus on the lower end of the plug to cause the shear pin 38 to break. This will cause the plug 39 and end cap 41 to move upwardly within the upper casing portion 14 against the biasing action of the second biasing spring 42. This action will cause the locking cap to move away from the end element 16 (as shown at FIG. 2) and will cause the locking balls to be released from being clamped between the end element 16 and the inner face of the inner tube 50. This releasing of the balls will then enable the locking cap to move to a position (not shown) away from the end element 16 and as result the first tube clamping means is deactivated fully.

To prevent the body 11 from moving outwardly from the inner tube 50 a second tube clamping means is provided which comprises a set of circumferentially spaced keys or collets 53 which are accommodated within a tapered groove 55 provided in the inner face of the inner tube 50 and which will engage with the outer face of the body 11 whereby any outward movement of the body 11 relative to the inner tube 50 will cause the collets to become frictionally engaged between the inner tube and the body 11.

The body 11 is retained in position within the inner tube 50 by the first and second tube clamping means whereby the first clamping means is released on the body being lowered into the hole such that the reference member is clamped into position to allow for slidable movement of the body within the inner tube while the second clamping means ensures that the resultant slidable movement of the body can only be inward with respect to the inner tube.

In use the body is located in the lower end of an inner tube as described above such that the lower casing portion of the body extends from the lower casing portion 13 of the inner tube as shown at FIG. 1 at which position the actuating rod 35 is located at its outermost position within the body 11, and the clamping rod 27 is located at a most remote position from the reference member 23 as shown at FIGS. 1 and 3. In addition, the pins 15 are located at their outermost positions relative to the body 11. On the introduction of the core orientator into the bore hole and being lowered onto the bottom of the bore hole, the actuating rod 35 will be depressed such that it moves into the body 11. This will cause the outer ends of the elongate pins 15 to become engaged with the bottom of the bore hole whereby the ends of the pins will provide a profile corresponding to the profile of the bore hole. In addition, the inward movement of the actuating rod 35 will bear upon the clamping rod 27 to cause it to bear against the reference member 23 and to clampingly engage the reference member 23 between the clamping rod and the annulus 19 and to cause the reference member to bear on the second bearing member 40. This will fix the reference member within the space 17. In addition this action will break the shear pin 38. This will in turn cause the upward movement of the locking cap 41 from the upper end of the body 11 and thus reduction of the frictional engagement of the locking balls between the wall of the inner tube 41 and the upper end of the body.

Because of the frictional retention of the clamping rod 27 within the bore of the body 11 by the O-rings 27, the reference member is held in its clamped position and because of the influence of the third biasing spring the first tube clamping means is held in its disengaged position. This will then cause the first biasing springs 37 to cause the slidable movement of the body along the actuating rod 35 to cause the body to move relative to the actuating rod away from the base of the bore hole and into the inner tube 50 beyond the outer end of the inner tube and the drill bit associated therewith (not shown) into the inner tube which will enable the core drill to be utilised to drill a core. The rotation of the drill bit and inner tube will cause the body to rotate about the actuating rod 35, while the continued operation of the drill bit will cause the body to move inwardly with the core.

On completion of the drilling operation the inner tube, the cut core and the body are extracted from the bore hole. The body is then opened by separating the lower portion from the body to expose the annulus and the portion of the reference face visible through the annulus whereby the graduations and compass markings on the reference face can be used to provide an indication of the inclination of the bore hole, the azimuth of the bore hole and the lowermost part of the bore hole in the region from which the core has been extracted while the array of the outer ends of the elongate rods provide an indication of the profile of the face of the upper end of the core.

The second embodiment as shown at FIGS. 4 and 5 differs from the first embodiment in regard to the nature of the space and the reference member supported thereby. In the case of the second embodiment the spaces 17 comprises a “ball compass” which comprises closed spherical reservoir which accommodates the reference member (not shown) in a liquid contained within the reservoir. The reference member is magnetised and is provided with compass indicia which at least comprise an indication of the position of the North and/or South Pole. The walls of the reservoir are transparent. The reference member is of the same form as that of the first embodiment with the exception its density approximates the density of the liquid. The reservoir is supported from the first bearing member 29 in opposed relation to the tapered space. On movement of the first bearing member inwardly the reservoir will bear upon the upper face of the tapered space to cause the shearing of the shear pin and the disengagement of the locking balls 51 of the first tube clamping means of the first embodiment as described above in regard to the first embodiment.

In addition, the clamping means is associated with a clamping ball 61 which is supported between the surface of the tapered space 21 and the reservoir and is able to move in an upward direction from a lowermost position on that surface. On the inward movement of the clamping rod 25 the reservoir is forced against the clamping ball to cause indentation of the wall of the reservoir and thus the fixing of the reference member in position.

On removal of the body from the bore hole and the opening of the body the reservoir is extracted form the body. Because of the engagement of the clamping ball 61 into the indentation formed in the wall of the reservoir the clamping ball remains fixed to the reservoir. By means of the location of the clamping ball on the reservoir and the reading of the reference face of the reference member through the wall of the reservoir the inclination of the bore hole, the lowest portion of the bore hole and the azimuth of the borehole in the region of the extracted core can be determined.

A further embodiment comprises a variation of the first embodiment and is of the same form with the exception that the space is sealed from the bore hole provided with a liquid to support the reference member.

It should be appreciated that the scope of the present invention is not to be limited to the particular scope of the embodiments described above and in particular the additional components of the core orientator of the embodiment such as the face orientator. 

1. A core orientator, comprising a body configured to be receivable in a bore hole and to be lowered into the bore hole, the body defining a space which in use is intended to receive a liquid, the space supporting a reference member which is at least substantially supported by the liquid, the reference member having a reference face with a centre, the reference member being weighted such that when the space is at least partially filled by the liquid, the centre will be uppermost, a clamping means adapted to clamp the reference member in position within the space on the lower end of the body being engaged with the bottom of the bore hole.
 2. A core orientator as claimed at claim 1 wherein the lower end of the body supports a face orientator having a face which in use is able to be forced into contact with the bottom of the bore hole and to provide an indication of the profile of the end of the bore hole.
 3. A core orientator as claimed at claim 1 wherein the reference member has a configuration of a sphere.
 4. A core orientator as claimed at claim 3 wherein the reference face of the reference member is provided with a set of circular graduations concentric with the centre.
 5. A core orientator as claimed at claim 1 wherein in use the core orientator is to be used in a borehole in which liquid is present, and the body is adapted to permit the entry of the liquid into the space on being located in the liquid within the borehole.
 6. A core orientator as claimed at claim 1 wherein the space accommodates the liquid.
 7. A core orientator as claimed at claim 6 wherein the space is defined by a closed reservoir having a wall which is deformable on engagement with the clamping means in order to fixable engage the reference member within the space, said deformation being permanent said space containing the reference member and liquid.
 8. A core orientator as claimed at claim 7 wherein the reservoir has the configuration of a sphere.
 9. A core orientator as claimed at claim 7 wherein the reservoir is removable from the body wherein in use the position of said deformation provides an indication of the position of the reservoir relative to the body.
 10. A core orientator as claimed at claim 7 wherein the clamping means is associated with a deformation means which is supported in the space proximate the reservoir and which is movable into engagement with the wall on the clamping means clampingly engaging the wall to cause the deformation means to cause said deformation of the wall.
 11. A core orientator as claimed at claim 10 wherein the deformation means comprises a separable element which on causing said deformation may be retained by the deformation.
 12. A core orientator as claimed at claim 10 wherein the deformation means comprises a ball element supported in the space between the reservoir and the clamping means.
 13. A core orientator as claimed at claim 1 wherein the reference member is magnetised to have a North and South Pole at opposed sides of the reference member, said reference member bearing indicial indicative of the location of the North and/or the South Pole.
 14. A core orientator as claimed at claim 13 wherein the poles are substantially equidistant from the reference face.
 15. A core orientator as claimed at claim 1 wherein the face orientator comprises a plurality of axial pin elements which are slidably received within the body such that a force of a predetermined magnitude is required in order to slid ably move the elements within the body.
 16. A core orientator as claimed at claim 1 wherein the clamping means comprises a clamping member slidably received in the body and extending between the one face and the space wherein the end of clamping member within the space is adapted to be engageable with the reference member, the upper end of the space being adapted to support the uppermost face of the reference member when engaged by the clamping member.
 17. A core orientator as claimed at claim 16 wherein the clamping member comprises an upper portion and a lower portion, both upper and lower portion being slidably received within the body along a common axis, a first locking means provided between the body and the one portion to retain the one portion in a position, the other portion being biased to an outermost position with respect to the face.
 18. A core orientator as claimed at claim 1 wherein the other end of the body is associated with a first tube clamping means which is adapted to clampingly retain the body within the inner tube of a core drill, said first tube clamping means being dis-engagable from the inner tube on the clamping means, clamping and engaging the reference member.
 19. A core orientator as claimed at claim 16 wherein a second clamping means is provided between the body and the inner tube, the second clamping means is adapted to clampingly engage the body within the tube to prevent axial movement of the body from the inner tube and permit axial movement of the body into the inner tube.
 20. A core orientator as claimed at claim 17 wherein the body is associated with a second clamping means which is adapted to retain the body within the inner tube of a core drill to prevent outward displacement of the body with relative to the inner tube.
 21. A core orientator as claimed at claim 1 wherein the density of the reference member approximates the density of the liquid.
 22. (canceled) 